Fuel Pump Relay question

[Ben Swann]

Temperature sensor (NTC) :
~2.5Kohm@ 20Deg. C/68 deg. F
< 2.5Kohm  warming; about 800ohm when engine warm
>2.5Kohm colder than 20 deg. C -> 4Kohm very cold

See Bently sec. 25.42 and 25.108.

No need to repeat what Tony suggests, but sensor is probably good.

Ben

[Date: Fri, 27 May 2005 10:08:36 -0700
From: Tony Lum <tlum at flash.net>
Subject: Re: Fuel Pump Relay question
To: Chris Hall <badcomrade at gmail.com>
Cc: quattro at audifans.com
Message-ID: <42975414.3010508 at flash.net>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

Chris Hall wrote:
> Latest on my 85 Coupe GT
>
> I tried to "jump" the wires to the "NCT" (ECU coolant temp sensor) and
> that didn't work.  I checked the resistance on that sensor, and it
> came up to be 2700 ohms or something like that... which I think I've
> read is pretty close to spec (2500 cold?).
>
> Last night I tried starting the car again, and it did that thing where
> it starts to combust, but never kicks in all the way.  I know the fuel
> pump -pumps- and I'm guessing it's providing enough pressure because I
> think it's only 4 or so years old...
>
> Fuel pump relay appears to be working as it should, and I even jumped
> the slots and still no starting.
>
> Someone please get back to me if that value for the ecu's coolant temp
> sensor is way off...
>
> Guess I'll have to check more things out tomorrow when I'm off work...
*sigh*
>
> Why do we love these cars so much again?   lol
>

Sounds like your temp sensor is working.  IME, the sensor reads around
100 ohms fully warmed up.  When bad, they're usually open or read like
100K ohms cold.  Are you sure you're getting spark? Check the Hall
sensor on the distributor.  Check the contacts and make sure all the
wires are fully seated with no corrosion on the contacts.  It would also
help to pull the connector on the ecu (next to the glove box) and see if
  those contacts are good and that the signal wires from the sensor are
also present on the ecu's connector.  Maker sure the idle/WOT switch is
working.  Your F.I. system is CIS-E, which means that the grey
differential pressure regulator that's attached to the fuel distributor
should be receiving some current.  To measure this you have to make up
an adapter to place a current meter in series with the DPR.  Should
measure something like 8-10 mA under normal conditions.

HTH,

Tony
'83 urq]